It’s happening again! Our wonderful cockles in the Whangateau Harbour are dying in what appears to be an event similar to that in 2009 when 80% of our cockles died.

A dead and gaping cockle lies moribund and stinking on the sand surface over the cockle beds off Lew’s Bay in the Whangateau Harbour.

In the summer of 2009 Whangateau Harbour residents noticed an awful smell coming off the harbour flats. It soon became obvious that it was caused by many thousands (in fact millions) of dead cockles rotting in the sun.

Sieving the sand out of the samples to enable the shellfish to be counted and measured. Eagleray feeding holes filled with water were handy on the upper shore. Without them samples would have to be carried several hundred metres to water for sieving

The annual survey of shellfish, particularly cockles, on two transects east of Horseshoe Island in the Whangateau Harbour, was successfully completed on Friday 28th March by ten students and several adult helpers. Mahurangi College science teacher Wendy Dunn organized the students into pairs for the task. As the shellfish beds in the Whangateau Harbour are currently closed, a special permit is required to carry out the surveys.

A school of several hundred young kahawai was seen in the channel behind Horseshoe Island on Saturday. This was the largest number of kahawai I have seen in this area, and is a very encouraging sign. There were also large numbers of adult parore, and the usual school of around 200 trevally which have grown since last summer. There were no juvenile snapper, however, which were common in the summer but have departed for winter.

With 8 to 10 metres visibility, this is the clearest I have seen the harbour waters since the big cockle die-off in 2009. There had been no rain or wind for several days, however, and the water on the coast is very clear at the moment too, which all helps the harbour’s water clarity.

Part of a school of hundreds of young kahawai in the channel behind Horseshoe Island on Saturday.

Parasites and bacteria implicated in the mass cockle deaths in the Whangateau Harbour. Closure of the shellfish beds is anticipated to allow them to recover.
A report from MAF Biosecurity has implicated coccidia and mycobacteria as the likely cause of the massive die-off which occurred this summer. The role of heat and very low tides is not clear but may have made the cockles more susceptible to infection.

The Cockle Mystery is now available for sale. This is the great little book written by Whangateau resident Ella Gerard while a Year 11 student at Mahurangi College. It graphically describes the cockle die-off and its consequences and is very entertaining. Copies are available for $20.00 by contacting Richard Gerard or Warkworth Print – 50% of all sales go the the HarbourCare Group.